Pyloric stenosis occurs in babies as a
result of thickening of the pyloric mus-
cle. W hen it occurs in adults, however,
the condition is due to scarring from a
p e p t ic u lc e r
s to m a c h c a n c e r.
Babies start projectile vomiting (profuse
vomiting in w hich the stomach con-
tents may be ejected several feet) two to
five weeks after birth. Adults with the
disorder vomit undigested food several
hours after a meal.
In infants,
u lt ra s o u n d s c a n n in g
is the pro-
cedure used for confirmation of the
diagnosis. In adults, however, diagnosis
is likely to be made by means of a
b a r i-
u m X -ra y e x a m in a tio n
and a
g a s t ro s c o p y
(examination of the stomach using a
viewing instrument).
In infants, surgical treatment involves
making an incision along the thickened
muscle. In adults, surgery is carried out
to correct the underlying cause.
In infantile pyloric stenosis, the
muscle surrounding the outlet
from the stomach is abnormally
thickened, as shown in the enlarged
drawing (below). The condition
occurs more often in male than
female babies and tends to run in
families - infants of a woman who
was affected with pyloric stenosis
as a baby may develop it.
o f muscle
p y lo ro p la s ty
An operation in w hich the pylorus (the
outlet leading from the stomach) is
widened in order to allow free passage
of food into the intestine. Pyloroplasty
may be performed as part of the surgery
for a
p e p t ic u lc e r
or may be performed
in order to prevent tightening of the
pyloric muscles after
v a g o to m y
of the vagus nerve to reduce stomach
acid production).
A prefix that is used to denote a rela-
tionship to
p u s
The prefix py- is also
used in the same way.
p y o d e rm a g a n g re n o s u m
A rare condition that is characterized by
ulcers, usually on the legs, that turn
into hard, painful areas surrounded by
discoloured skin. Pyoderma gangreno-
sum occurs as a rare complication in
u lc e ra tiv e c o lit is
p y o g e n ic g ra n u lo m a
A common, noncancerous skin tumour
that develops on exposed areas after
m inor
removed surgically, by
e le c t ro c a u te ry
c ry o s u r g e r y
p y ra z in a m id e
A drug sometimes used to treat
t u b e rc u -
lo s is
Possible adverse effects are nausea,
joint pains,
g o u t
and liver damage.
p y re x ia
A medical term for
f e v e r
p y re x ia o f u n k n o w n o rig in
more, w ith no apparent cause. It is usu-
ally due to an illness that is difficult to
or a common disease that
appears in an unusual way. Such illness-
es include viral infections;
t u b e rc u lo s is
cancer, particularly
ly m p h o m a
c o lla -
g e n d is e a s e s
such as systemic
lu p u s
e ry th e m a to s u s
t e m p o ra l a rt e rit is
. An-
of pyrexia
unknown origin is a reaction to a
d r u g
p y rid o x in e
v ita m in
B c o m p le x
Dietary deficiency
of this vitamin is
very rare but can be induced by some
drugs. Supplements of pyridoxine
to 100 mg per day) are sometimes used
to treat
p re m e n s t ru a l s y n d r o m e
. T h e r e
is a
possible risk of toxicity if high doses of
the supplement are taken long term.
p y rim e th a m in e
A drug that is used in combination with
other drugs to treat resistant
m a la ria
p y ro g e n
A substance that produces
f e v e r
applied to
released by white
b lo o d c e lls
in response
to infections. The word is also some-
released by microorganisms.
p y ro m a n ia
A persistent impulse to start fires. It is
more often seen in males, and may be
associated with a low IQ, alcohol abuse,
and a
p s y c h o s e x u a l d is o r d e r
p y ru v a te k in a s e d e fic ie n c y
A disorder in w hich there are abnor-
mally low levels of an
e n z y m e
pyruvate kinase, w hich is carried in
r e d
b lo o d c e lls
Normally, pyruvate kinase
aids the breakdown of glucose to create
energy in
a n a e ro b ic
(low-oxygen) con-
ditions. If there is a deficiency of the
enzyme, the red cells cannot generate
enough energy for themselves; they also
develop chemical imbalances that cause
them to be destroyed prematurely by
the spleen, thereby
causing anaemia
a n a e m ia , h a e m o ly tic
) and enlarge-
ment of the spleen. The disorder is
usually the result of an autosomal reces-
sive gene defect (see
g e n e t ic d is o r d e r s
The severity
of the disease varies.
Most people require no treatment.
B lo o d
t ra n s fu s io n s
may be needed in some
cases, particularly when the person is
acute illness or pregnancy), at w hich
times the disease tends to be worse.
S p le n e c t o m y
(removal of the spleen) may
be recommended in severe cases.
p y u ria
The presence of
w h ite b lo o d c e lls
in the
u r in e
w hich is often an indication of an
infection of a
k id n e y
u r in a r y tra ct in f e c -
tio n
and inflammation.
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